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Ottawa team unravelling brain damage in multiple sclerosis

Last Updated Wed, 21 Dec 2005 13:47:38 EST
CBC News
The puzzle of how nerve coatings are damaged in the brains
of people with multiple sclerosis may have been solved by a
Canadian-led research team.
Nerve fibres that send electrical signals in the brain are
coated in a fatty sheath called myelin, which acts as an
insulator, like a plastic coating covering a copper wire.
If myelin gets damaged in multiple
sclerosis or spinal cord injuries,
the electrical circuit may misfire or
not fire at all.
Neurologist Dr. Peter Stys of the
Ottawa Health Research Institute
and his colleagues proposed a
reason why myelin becomes
damaged and invented a way to
test the idea in the lab.
The researchers showed myelin
contains specialized receptors for glutamate, a
neurotransmitter that transmits signals to brain cells.
They also found chemicals that block the receptor can reduce
myelin damage.
"Such a mechanism may represent a potentially important
therapeutic target in disorders in which [myelin damage] is a
prominent feature," the researchers write in Thursday's
online issue of the journal Nature.
The myelin coating on nerves is
damaged in people with MS.

The laboratory findings need to be confirmed and tested in
animals before a potential drug can be tried by humans.
To make the discovery, Stys's team invented a state-of-theart
laser scanning microscope technique to look closely at
living myelin from a rat model.
They discovered the surface of myelin has tiny open pores
that provide a gateway for calcium to enter. If too much
calcium enters, it can injure the myelin and affect our ability
to walk, talk or see.
Stys and his team also found a drug already on the market to
treat brain disease can block the pores of the myelin sheath.
"When we put these drugs on it, it greatly reduced the injury
to the myelin and greatly improved the ability of these nerve
fibres to conduct and transmit nerve impulses," Stys said.
The findings help fill in the details of what molecules are
involved and how they interact in MS, agreed Dr. Stephen
Waxman, neurology chair at Yale University School of
Medicine. He was not involved in the research.
The research was funded by the National Institute of
Neurological Disorders and Stroke, the Canadian Institutes of
Health Research, the Heart and Stroke Foundation of Ontario,
the Canadian Institute for Photonic Innovations and private
donors.
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Submitted  1/4/2006 10:27:34 PM